Train dispatching system for railroads



June 1, 1937. N. D. PRESTON.

TRAIN DISPATCHING SYSTEM FOR RAILROADS Filed-June 16, 1927 7 Sheets-Sheet 1 June l, 1937. y vN. D. PRESTON v TRAIN DISPATCHING* SYSTEM FOR RAILROADS Filed June 16,' 1927 '7 sheets-sheet '2 om zt.

INVENTOR June l, 1937. N. D. PRESTON TRAIN DISPATGHING SYSTEM FOR RAILROADS Filed June 16, 1927 7 Sheets-Sheet 5 llllllllllllj.

lJune l, 1937.

N. D. PRESION TRAIN DISPATCHING SYSTEM FOR RAILROADS Filed June 16, 1927 '7 Sheetfs-Sheet 4 v INNTO 'lilll June 1, 1937. N. D. PRESTON TRAIN DISPATCHING SYSTEM FOR RAILROADS 7 sheets-sheet Filed June 16, 1927 O D V N. D. PRESTON T'RAIN DISPATCHING SYSTEM FOR RAILROADS Junef l, 1937.

Filed June 16, 1927 7 Sheets-Sheet 6 June l, 1937. N. D. PREsToN TRAIN DISPATCHING SYSTEM FOR RAILROADS '7 Sheets-Sheet 7 Filed June 16, 1927 Num Patented `une 1., 1937 UNITED STATES TRAIN DISPATCHING SYSTEM FOR RAILROADS Neil D. Preston, Rochester, N. Y., assigner to General Railway Signal Company, Rochester,

Application June 16, 1927, Serial No. 199,325

83 Claims.

This invention relates to systems for dispatching trains on railroads by signal indications under the control of an operator or dispatcher at a central station.

One object of the invention is to provide for the control of the wayside signalsof a single track railroad so that the direction of traffic is determined by the position of levers, or similar manually controlled devices, independently of the sequence in .which these levers arek operated, 01 how quickly they are operated one after another.

Another object is to provide a power-operated switch, under the control of the operator, with the necessary approach locking protection, which is controlled by levers or the like, separate from the levers determining the direction of traic.

A further object of the invention is to provide the necessary control for the operation of the signals and switches by selectors, preferably of the synchronous type as distinguished from the code type, thereby economizing in line wire and facilitating the economical extension of the system.

A still further object is to provide means for indicating at all times at the central station the location of trains, and their direction of movement, synchronous type selectors being employed for this purpose in such a way that several indications of train location may be transmtted successively within such a limited time as to be substantially simultaneous.

'Ihe invention further contemplates an automatically operated recorder providing a grap-hic Chart which constitutes a complete record of train operation, and which in conjunction with the track diagram indicating at any time the existing status of train location provides the necessary information to the operator to enable him to handle the traine expeditiously. The chart thus automatically made is alsor arranged so that the operator may make various notations thereon, such as forecasts of meets, which will materially assist him in manipulating the system.

The indication of train location, or direction of movement, is preferably provided by an illuminated track diagram, which automatically changes as trains move. In connection with this track diagram, an audible signal is preferably provided to call attention to a change in train location; and there is also preferably provided ymeans for enabling the operator to distinguish the particular lamp or indicator 'that has just responded. y

IIn connection with the selector system for control of train indication, special means are provided so that the various selectors vat the different way stations along the track are 'opera-ting only when required toreceive a control indication or transmit a change in the indication 5 of train location.

Various other objects, vcharacteristic features, and advantages ofthe system and its various modifications herein disclosed will Vbe lin part obvious, and in .part pointed out as the description progresses.

Figs. 1A and 1B illustrate the essential circuits of an A. P. B. signaling system `having superimposed thereon means for controlling :the switch of such system and dispatch trains over such system by remote controlled Wayside signals in accordance with the present invention, of which many of the novel features are shown conventionally herein and are shown specifically in the remaining figures of the drawings, land 20 more particularly showing the control circuits of the system; Y

Fig. 2 shows modified control circuits yfor the system of Figs. 1A and 1B;

Fig. 3 shows the switch machine-control and the approach locking circuits for the systems shown in Figs. 1A, 1B and 2.

Figs. 4A and 4B illustrate 'the cont-rol and indication selector system conventionally shown in the systems of Figs. 1A, 1B and 2. 30

Fig. 5l shows the miniature track layout and control board at the dispatchers oice, and

' Figs. 6 and 7 show `on a larger Ascale than Fig. 5 a portion of a recorder for recording entirely automatically the movement of all trains.

Signal control circuits While Various features of this invention are applicable to the control of switchesand signals at isolated locations, either on single or double track, the invention has been shown applied to a single track railroad, which' is Eto tbe equippedv with some suitable form of block signaling system, preferably of the Well known absolutepermissive-block type. Figs. 1A and 1B show in a simplified and diagrammatic manner one embodiment of the control circuits for the signals of an A. P. B. system as modied and adaptedr in accordance with this invention. Y

Referring to Figs. 1A and 1B, in which the portion of track shown comprises one siding SD, one end of another siding SD1, and a stretch' of single track -O between these sidings. The track, including the siding, 'is provided with 'in-V sulated track sections a, b, etc. in 'a manner CTI obvious to those skilled in the art. The track batteries have been shown, conventionally, and the track relays for these various track sections are indicated conventionally by dotted lines. The track sections a, d, and y' are short detector track circuits at the ends of the sidings, the switch points being suitably cross-bonded in a well known way.

The signals, which may be of any suitable type, shown conventionally as of the semaphore type, for the siding SD and single track stretch O shown in Figs. 1A and 1B, are designated l, Id 2, 2d, 3, 4, 5, 5d, 6 and 6d. The signals 6 and 6d govern traffic in one direction (conveniently termed eastbound trac as indicated by the arrow E) onto the main track opposite the siding, and into the siding, respectively, These signals 6 and 6d are conveniently called entering signals. The signals I and Id are likewise entering signals for westbound traftlc at the siding SD or SD1. The signals 5 and 5d, conveniently termed starting signals. govern westbound trafc from the main track opposite the siding, and from the siding, respectively, into the single track stretch O. The signals 2 and 2d are similar starting signals for eastbound traflic from the siding SD; and the signals 5 and 5d are also starting signals for westbound traffic from the siding SD1. The stretch of single track O between the sidings SD and SD1 is preferably provided with one or more pairs of intermediate signals, arranged opposite or in staggered relation, in accordance with the well known practice in the A. P. B. system. Two intermediate signals 3 and 4- are shown. The

" intermediate signals 3 and 4 are permissive automatic block signals; but the starting signals, 2, 2d, 5 and 5d are absolute stop-and-stay signals. When these absolute signals are at stop, they can not be passed except under special order and with suitable flagging protection in accordance with the rules. For reasons hereinafter eX- plained, the entering signals, as I, Id, 6 and 6d, are preferably provided with auxiliary arms or lights 'I, as shown, for the purpose of giving these signals either an absolute stop-and-stay indication, or a permissive stop indication, under the control of the operator. f Y

In order to simplify the drawings, the control circuits are shown only for the clear and stop indications of the signals; but it should be understood that three-position signals, or their home and distant equivalent, are employed in practice, the caution indication or distant signal being controlled in the well known way by addiy tional line circuits or a polarized line circuit.

The switches `are preferably power-operated by an electric switch machine, shown conventionally at SM in Figs. 1A and 1B. Each switch is provided with contacts, either as a separate switch circuit controller, or as a part of the switch machine, which are closed when the switch is in a corresponding extreme position and locked. These switch controller contacts are shown conventionally at I0, I4 and 29.

At each end of each siding is a signal control relay Z, operatively` connected in some suitable way, indicated conventionally by dash lines 45, as by a line circuit or a system of selectors, as hereinafter described, to a lever LZ, or a corresponding manually operable control device, located in the dispatchers office at the central control point. At each end of each siding is also a switch control relay SW, similarly connected by dotted line 46 to a lever LS. These relays and levers for the other 'siding ends shown in Figs. 1A and 1B are connected by suitable means conventionally shown by similar dotted lines and are given the same reference characters with distinctive exponents. The signal control levers for the opposite ends of each single track section between sidings, as the levers LZ and LZ2, are preferably provided with a mechanical interlock, so that they can not be simultaneously shifted to extreme positions to set up conflicting directions of trac for the single track stretch. As shown, these levers LZ, LZ2 which are movable to the right or to the left from the middle position shown, are provided with extensions cooperating with a sliding bar 48 with stops thereon in such a way that these levers can not be moved towards each other at the same time. If the lever LZ is shifted to the right, for example, the lever LZ2 can not be shifted to the left. The switch control levers LS and LS2 are preferably arranged to move up and down between two extreme positions corresponding to the switch points normal or reverse.

The control for the corresponding signals of the various passing sidings are identical and therefore have been given like reference characters. The control for signals I and Id is the same as that of signals 6 and 6d, except an opposite direction of traffic is involved. Similarly, the control circuits for the pairs of starting signals 2-2d, and 5-5d are substantially the same. Consequently, an explanation of the control of the entering signals 5 and 6d and the starting signals 42 and 2d is enough to make clear the complete organization of circuits.

In order to avoid complication of the drawings by necessary circuit wires some of the circuits have been shown terminating at the end of a source of current or a mid-point of such source. In the particular arrangement shown direct current is to be used, although alternating current can be used if desired, and the positive side of the source or battery'is designated B, the negative terminal is designated N and the mid-point, if such is used or the terminal connected to common wire is designated C.

Referring rst to the starting signals 2 and 2d, their control circuits as shown in the simplified diagram may be readily traced from the positive B of the battery, through the neutral armature I 2 of signal control relay Z, polar armature I3 to the right or left, through the switch circuit controller contacts I4 normal or reverse, through the mech'- anism signals 2 or 2d, and through the front contact I5 of the line relay 2H, to negative battery marked C.

'I'he line circuit for this line relay 2H (starting at common C) includes the front contact I6 of the detector track section d, front contacts Il and IS of the track sections e and f intervening between the signals 2 and the next eastbound intermediate signal 4, and through a front contact I9 ofthe relay 4H controlling said signal 4, in multiple with the front contact 20 of the directional stick relay 4S at said signal 4, to negative battery N. This directional stick relay 4S is characteristic of the A. P. B. system, such as is disclosed, for example, in the U. S. patent to S. N. Wight No. 1,294,736, dated Feb. 18, 1919, and is picked up only by an eastbound train traveling past the signal 4, and.- is stuck up so long as the relay 4H is de-energized.

The line circuit for the relay 4H includes the front contacts 2l, 22 and 23 of the track relays for sections g, h and i, and circuit controllers 24 and 25 on the opposing starting signals 5 and *.i closed only if these signals are at stop to a battery, and in the event the caution control is added to N or B depending on the indicating condition of signals 6 and 6d.

Since the control circuits for the home or line relays 5H and 3H are exactly the same as those of the line relays 2H and 4H, respectively, J'ust traced except that they extend in the opposite direction in the single track stretch like parts thereof are given like reference characters with a distinctive exponent two.

vReferring now to the control of the entering signals 6 and 51, these signals are controlled respectively by relays 5H and EdH. The energizing circuit for the relay 6H may be traced as fol- 1ows:-commencing at positive terminal B of a battery, through the neutral contact |21 of the relay Z1, its polar armature |31 to the right, wires 261, 271 and 281, relay 6H, switch circuit controller contact 291 closed in the normal position of the switch, through the front contacts 301 and 3i1 of the track relays for the detector track circuit a, and the track circuit bin the main track opposite the siding, and through a back contact 321 of the relay IH controlling the opposing signal I to C. The energizing circuit for the relay dH is much the same, passing through switch circuit controller contact 291 closed in the reverse position of the switch, a front contact 331 of the track relay for the detector track circuit a, front contact 341 of the siding track circuit c, and back contact 351 of the relay IdI-I controlling the opposing take-siding signal I1 to C. The circuits for the relays I and Id are exactly the same as r those just traced except governed by the opposite direction of trailic and therefore like parts have been given like reference characters with the exponent one omitted.

The manner in which the signals I, I d, E and 6d are controlled by relays IH, IdH, 5H and 61H is obvious from the circuits shown in the drawings.

From a consideration of these circuits, it can be seen that the signal control lever LZ, for example, in one operated positio-n (to the right in the arl rangement shown) tends to clear the eastbound startingsignals 2 and 2d, one or the other of these signals clearing, depending upon the position of the switch, providing the opposing starting signals 5 and 5d are at stop, that there is no opposing westbound train in the stretch of single track, and n eastbound train between signal 2 and the signal Il. In short, the lever LZ, when moved to the right, will set up eastbound traic (to the right) from the east end of the siding SD to the entering signals and 6d at the west end of the siding SD1, that is, over the stretch of single track O. For westbound traic over this stretch of single track O, the other lever LZ2 is moved to the left. The mechanical interlock between the levers LZ and LZ2 prevents moving them accidentally to the right and left respectively at the same time, which would tend to allow eastbound and westbound trains to enter the same stretch of single track. On account of the electrical interlock between the opposing starting signals. 2--21 and 5--51 through the contacts 24 and 25, however, conflicting signal indications could not be given in spite of the omission of the mechanical interlock, the direction of traffic set up in the event of failure or omission of a mechanical interlock being that corresponding to the lever rst moved and rst effective through the line relays and their control circuits in holding the opposing starting signals at stop.

If the signal Vcontrol-lever LZ .is moved tothe left, westbound'traiic for the siding and main trackopposite the siding is set up, and the signal Ifor I d may clear, depending upon the position of the switch, providing the corresponding track section b or c is not then occupied, and further providing that the corresponding opposing signal or 6d is in the stop position. Eastbound tra-nic through the siding is controlled by moving the signal control lever LZ1 to the right.

Since the electrical interlock is between the upper arms 'I and 6 and between the lower'arms Id and iid, trains traveling in opposite directions maybe allowed to enter respectively either the siding or the main track opposite the siding; but the two signals I and 6, and likewise Id and Sd, governing traffic in opposite directions into the same pieces of track can not be cleared simultaneously, thereby affording ample protection for opposing train movements both into the siding and into the main track opposite the siding, without the use of an overlap.

Occasionally in practice it may be desirable to allow two trains, particularly one train and a light engine, traveling either in the same direction or in opposite directions, to enter the same piece of track either on the siding, or on the main track opposite the siding; and to enable this to be-done with a high degree of protection, the entering signals I, id, E and 6d are preferably provided with auxiliary permissive indications. Referring to the signals I and Id, for each signal there is an additional indicating means, such as a lamp, call-onA arm, or the like, which may be energized to give a permissive aspect to the corresponding signal when the relay Z is energized by the operator, and the switch points are in the corresponding position and locked.

Considering the permissive aspect signal 'I of the signal I for instance, this lamp is energized through contact I3, swung to the left, of the relay Z, and the contact Il! of the switch machine when in its normal position, and therefore is lighted to indicate permissive proceed in the event there is a train directly ahead on the main track of the passing Siding holding the signal I at stop when such signal l is otherwise in a condition to clear, namely, with the relay Z and the corresponding track switch in the main track position.

By virtue of this arrangement the operator i can, if he wishes, permit two trains to enter the same portion of track, under the restrictions characteristic of a permissive stop indication, provided the switch points are safe. For example, assuming the operator wishes to put a westbound train, followed by a light engine, on the siding SD, he operates the lever LS to set the switch in the reverse position for the siding, then shifts the signal control lever LZ to the left, energizing the relay Z, and permitting the lower arm signal Id to clear. After this train arrives and enters the siding, it of course holds the signal Id at stop; but since the operator maintains his lever LZ shifted to the left and the relay Z energized, the signal Id is given a permissive aspect by the lighting of its call on signal lamp 'I the energizing circuit of which is readily traced, permitting the following light engine to pass on the siding, knowing that the switch points may be safely run over and that the signal is held at stop because of a train ahead or other obstruction. The following light engine, of course, proceeds atlow speed prepared to stop short of any obstruction. :It .will be evident that the operator can permit two trains to follow one another into the stretch of main track opposite the siding in the same way. Likewise, he can permit two trains, traveling in opposite directions, to enter either the stretch of main track opposite the siding, or move on the siding. In such a case, the operator would preferably keep both entering signals at stop, and issue his instructions to the rst train arrivingand calling up over the telephone (which in practice would be installed at each siding end), in order that the rst train arriving may leave room for the second. Also, if desired, the rules may provide that the permissive indications of the entering signals shall not be accepted without specific information from the operator over the telephone.

Modified signal control circuits Fig. 2 illustrates how the signal control circuits of Figs. lA and 1B may be governed by relays Z and SW, controlled by the operator, in a different way. In this modied arrangement, there is one lever, designated LZ-LZ2 for controlling the direction of traffic over the single track stretch O. The switch control lever LS has a neutral or intermediate position, as well as two extreme positions. The relays Z and Z2 at the opposite ends of the stretch of single track are operated simultaneously with the same polarity, by being connected to the same control circuit from the tower, or to like points on the controlling selectors, or by any other suitable arrangement. Thus, when the operator throws the signal control lever LZ-LZ2 to the right, to set up eastbound trafc, both the relays Z and Z2 are operated to move their polar armatures to the right, tending to clear signals 2 and 2d, and signals 6 and 6d. In other words, the operator selects the direction of traiiic from one end of the passing siding through the adjacent single track stretch, and through the next adjacent siding, up to the leaving signals for that adjacent siding. With a given direction of trafc through the siding set up, the train takes either the siding or the main track depending on the position of the switch. The

clearing of the starting and entering vsignals at each end of each siding, however, is dependent upon the energization of the corresponding switch relay SW, as well as the relay Z, the neutral armature I2 of the relay Z being connected to battery through a front neutral contact Il of the neutral polar relay SW. Consequently, the operator, by manipulation of the switch lever LS, is able to hold one train, while letting another proceed, or perform various other movements to take care of the diierent conditions that may occur in practice. In other words the relays Z and Z2 in this embodiment primarily determine the direction of traic for the single track section O, although they may also be used to stop traffic, whereas the switch machine relays may be used to hold the signals at one end of said section at stop without interfering with the movement oi traiic at the -other end of such section.

Switch control and approach locking Fig. 3 illustrates the preferred arrangement of control circuits for the switch machine and approach locking. Although the switch machine control circuit and the approach locking control mechanism associated therewith for the switch at the east end of siding SD only has been shown, it is deemed that this is sufficient since all switch machines are controlled in the same way and the approach locking relay circuits are the same considering their relation to the passing siding. The switch is operated to the normal or reverse position by energizing the relay SW with one polarity or another. It is contemplated that the switch operating mechanism will be of the electric motor type, such as disclosed for example in the U. S. patent to W. K. Howe, No. 1,288,897 dated Dec. 24, 1918. This machine includes contacts 50 and 5i shifted from one extreme position (normal as shown) to the other extreme position, if the switch machine has completed its cycle of operation and the points are locked.

Another pair of contacts 52 and 53 are alternately closed when the switch machine is in the full normal or full reverse condition and are both closed while the switch is in midstroke. Magnets NM and RM electrically operate contacts to either of two extreme positions; and these magnets are energized over circuits controlled by relays NR and RR in series with a front co-ntact 5d of an approach locking relay LR.

Assuming the switch to be in the normal position as shown, when the operator energizes the relay SW with current of opposite polarity the relay RR is energized, through a circuit readily traced on the drawings and including the contact 52 closed with the switch machine in the normal position. Assuming there is no approaching train and the approach locking relay LR is energized and its front Contact 54 is closed, then the reverse operating magnet RM is energized, shifting the contacts 55 and 56 and closing a reverse operating circuit for the motor from battery 5'! through wires 5l'a and 58, contact 55 (shifted to dotted position), Wire 59, contact 5U, motor armature, contact 5| normal, wire 60, motor eld and wires 6| and 62 back to the battery.

When the switch machine starts operating, it shifts contacts 52 and 53 to the middle position; and when the switch machine completes its operation, the contacts 50 and 5l are shifted to the reverse dotted position, thus closing a snubbing circuit through the resistance 63, including the motor armature and field reversely connected. This snubbing circuit comprises the following:- resistance 63, wire 64, contact 56 reversed, wire 65, contact 50 reversed, wire 66, armature, wire 61, contact 5l reversed, eld winding, and wire Si back toi resistance 63.

While the switch is in mid-stroke, both pairs of contacts 52 and 53 are closed, permitting energization of either relay NR or RR (assuming the approach locking relay LR to be energized), so that the switch machine may be reversed in mid-stroke by the operator. in mid-stroke is desirable because it sometimes permits the switch to be thrown by repeated operations when it could not otherwise be thrown on account of snow, lumps of coal, or other obstructions in the points.

Referring now to the approach locking protection, current can not be applied to either of the operating magnets NM or RM to cause operation of the switch from its then existing position, unless the approach locking relay LR is energized. If desired, the approached locking relay LR, if de-energized, may be used to cut off the switch machine battery, or short-circuit the armature and eld of the motor, or the like, as additional protection.

The energizing or control circuit for the approach lockingv relay LR may be traced as follows1 Commencing at B, (near signal 3) through circuit controller contact 'I0 on said signal 3 closed between zero and 45 degrees, in multiple Such reversibility with wire 'I2 and the front contact 91 of the relay of the track section g next in the rear of signal 3, wire 13, front contact 'I4 of the stick relay SL,` wire l5, circuit controllerY contact 76 on signal Id closed in the Zero degree position, wire TI, circuit controller 'i8 on signal I closed only in the zero degree position, wire 19, circuit controller 8G of signal 2d closed in the zero degree position, wire 8 I, circuit controller 82 on the signal 2l closed in the zero degree position, wire 83, front contact 84, of track relay of detector track section d, wire 85, relay LR, wire 86, front contact 8l of stick relay SLI, wire 88, and then either through wire 89 and front contact 90 of the track relay of track section next in rear of signals 6 and 6d, or along wire 9! through circuit controller 92 on signal 6 closed from zero to 45 degrees, wire 93, through a similar circuit controller 94 of the,

signal 6d, to common wire C.

It will be observed that the relay LR is deenergized if the detector track section al is occupied; and hence the switch can not be thrown under the train. Also, the relay LR is not'energized unless all of the signals at the switch I, Id, 2 and 2d are in the stop position, blocking train movement inv either direction over the switch. The other control for the relay LR is intended to de-energize the relay LR and prevent operation of the switch in case there is a train approaching the switch under aproceed indication. If the train is approaching the switch under a caution indication, .it will be slowing down and will be brought to a stop at the signals I, Id, 2 and 2d. In other words, if a train, approaching the switch from either direction, has received and accepted a signal indication permitting it to approach the switch at speed and pass over it, then the relay LR is de-energized and the switch can not be operated.

Referring to the control circuit for the relay LR at the signal 3, if this signal 3 is in the 90 degree or clear position, the'energization of the relay LR depends for its current upon the front contact 91 of the track relay of the section g next in the rear of said signal 3, so that when a westbound train enters the track section g, with the signal 3 in the clear position, the relay LR is de-energized. This, of course, means that the signals I and Id indicate caution or proceed.

Whenever the operator energizes the switch control relay SW in a direction to operate the switch from its then existing position, the resultant energization of either of the relays NR or RR interrupts at their back contacts 98 or 99 the circuits for clearing the signals I, Id, 2 and 2d, so that these signals assume the stop position.

If the signal 3 reaches its 45 degree or caution position, and the signal circuit controller 'I0' is closed before a west-bound approaching train passes it, then the relay LR is energized, notwithstanding the opening of the iront contact 9i of the track relay of section g, because with the signal 3 at caution, the current controller 'I0 is closed and shunts the front contact 97.

If, however, the train passes the signal 3, while in its clear position, the opening of the front contact It! of the track relay for section f breaks the stick circuit for the stick relay SL, which may be traced as followsp-terminal battery B through front Contact IIJI of track relay for section f, wiresr IZ and H33, contact |04 of relay SL, wire IBS, relay SL to the other side N of the battery. The pick-up circuit for the relay SL from terminal B through the front contact IIlIa of the signal relay 3H and wires IU'I and I 05; is also broken when the train passes the signal 3, since the energizing circuit for the relay 3H includes a front contact of the track relay for section f (see Fig. 1B). If signals is in the caution position when the westbound train in question passes it, and opens the front contact IIlIV of track relay for section f, the stick relay SL isY maintained energized through the circuit controller I on the signal 3 closed from zero to45 degrees. The stick relay SL, when oncede-energized by a westbound train passing the signal 3 in the clear position, is automatically again energized by its pick-up circuit if that train has advanced beyond the signals I and I@1 and out of the detector track section d, so that the relay 3H may pick up. Y

In the same way the stick relay SL affords ap-J.. proach locking protection for a west bound train approaching the switch under consideration when such train accepts the signal 3 in the rear at proceed, the stick relay SL1 affords such protection for east boundtrains. The problem for east boundv trains is, however, more difcult, becauseV of thel additional signals and possible train movements involved. The pick-up circuit for the relay SL1 may be traced as fol1ows:-From either B, signal contact II closed when the signal 6d is in thev caution or stop. position, wire III,l sig-` nal contact I I2 closed when the signali isin. the caution or stop position, wire II3, or B, contact II4 of the relay of detector track circuit a, then along wires II5 and IIS, backcontact II1- of detector track relay of section d, wires I I8 and I I9, through winding of relay SL1 to C. The stick circuit for this relay is exactly the same as-the pick up circuit just traced except that theY stick contact |20 is substituted for the relay contact From the consideration of these circuits it is noted that a through east bound train accepting either the signal 6 or 6d at clean. the relay SL1 is de-energized, irrespective of whether such train moves over the main track or the siding,

and that such train restores relay SL1 to its normal condition when it passes over detector track` section cl. Dropping of the relay SL]L in response to a train accepting signal 6 or 6d at clear is assured in the same way as is dropping ofrelay SL under similar conditions.

The arrangement shown is thus one which prevents switch machine operation when trains are approaching the switch in either direction in response to a clear indication of adistant signal, but does not cause such locking for departing trains or for approaching trains accepting the distant signals at caution or stop. Also, if there is a train standing onthe detector track circuit (such as d) at such switch, thev switch machine control apparatus is such that, if the switch machine has once beenstarted and lock relay LR is immediately thereafter de-energized for any reason, this will not prevent the cornpletion of the operating stroke, although both ma-gnets RM and NM are de-energizedbyv opening of contact 54, since the contacts 55 and 56` operated by said magnets remain where put.

Since there may be times when, on account of peculiar train movements, derangements of circuits, or some other reason, the approach locking is effective when the switch should be thrown, or for any other reason the switch machine can not be operated asv desired, I prefer to use with the switch a dual selector with a hand-throw mechanism, such as disclosed, for example, in the application of W. K. Howe, Ser. No. 160,679, led Jan. 12, 1927.

One characteristic feature of this scheme of approach locking is that the indications of the signals accepted by a train approaching the switch determine whether or not the approach locking shall be effective, rather than the presence of a train within certain approach locking limits. In this connection, the front contacts 90 and 91 of the track relays for the track sections next in the rear of the signals 3 and S-Gd may be omitted, if it is desired to rely on the circuit controllers on these signals. The circuit controllers corresponding to 10 and |00 of signal 3 should be made slow-acting, if light signals are used, so as assure that the relay LR will not be energized in case a train passes the signals 3 and 6-6d just at the time their indication is being changed to caution.

Selector system The electrical intercontrol between the central station of the operator or, dispatcher and the various sidings has to provide for selective energization of the signal control relays Z and the switch machine relays SW at the several sidings, and also has to provide for the transmission of a sufficient number of indications of train movement to enable the dispatcher to know enough about the location and direction of movements of trains to operate the switches and permit clearing of the signals. 'I'he various relays Z and SW may be controlled through a suitable selector system of the usual code type, the transmission of a particular code over a pair of wires acting through a code responsive selector to energize a particular Z relay with one polarity of current, another code with another polarity of current, and another code to deenergize that relay, and so on. With the code type of selector, however, each controlling function must be performed separately by a distinctive code, and enough time must elapse between the transmission of each code to avoid improper operation. While the operator may be relied upon to avoid confusion of codes by attempting to operate the relays Z and SW too quickly one after another, or automatic means may be employed to assure absolute segregation of code impulses, it is preferred to use a code transmission system of what is conventionally termed the synchronous type, in which a single line circuit is used successively at frequent intervals to establish a segregated control circuit between the central station and each relay or other device to be controlled in turn.

The indications of train location, that is, repeating in the central station or dispatchers ofi'ice the de-energization of detector track relays, or the track relays of other track sections, can not be readily handled by selectors of the usual code type, since two or more track relays may be operated at exactly the same time and confusion of the code impulses results. The synchronoustype of code system, however, permits the transmission of indications from the different track sections in succession so quickly one after another that the indications from the several track sections are suiiciently simultaneous for the purposes of dispatching trains.

While the code system for transmission of relay control and for the transmission of train indications may be carried over Separate line wires, and with different types of s eleQtQrS, With tact certain advantages, economy of apparatus and line wire makes it desirable to handle both control and train indication With the same selector, so that the apparatus is adaptable for both control and train indication functions. A preferred form of this invention employs this arrangement. Also, in accordance with this invention, special provision is made so that the selectors at the sidings are normally at rest, and are operated only where it is necessary to transmit an indication of change of train location, or when a control code is transmitted to change the energized condition of one of the control relays Z or SW.

Figs. 4A and 4B illustrate diagrammatically and conventionally one specific embodiment of novel means for performing both the signal control and train indication functions by synchronous selectors over a single line wire and the common return wire.

Referring to Figs. 4A and 4B the apparatus at the central station or dispatchers office, shown at the left hand side of these gures, that is on Fig. 4A, is enclosed within the dotted square DO. A shaft |30 indicated by a dash line,- is continuously rotated by a motor M of any suitable type, preferably a direct current compound wound motor with reasonably good speed regulation, although the speed of the shaft may vary through wide margins without affecting the operation of the system. A switch |3| may be used to stop the motor when the system is not in use. Fixed to the shaft is a make-and-break device, shown as a pair of brushes |32 and |33 cooperating with a toothed conducting rim |34 and insulation |35 to momentarily make and break electrical connection between these brushes |32 and |33 in an obvious manner. This wheel |34--I35 also carries a cam |36 engaging a roller |31 forcing a spring contact |38 nger insulated therefrom against a stationary con- |39. A selector arm |40 fastened to the shaft |30 bears on the contact ring |4| and contacts successively with a plurality of contact buttons 1st, 2nd, 3rd, 4th, etc. as the shaft rotates. Another arm |43 on said shaft engages a pair of contacts |44-I45 in the initial 0r zero degree position of the shaft, and establishes electrical connection between an interrupted ring |46 and a plurality of contact points, such as |41, as. the shaft rotates through another portion of its revolution.

Each lever, only one lever LS being shown connected, is provided with a cam |50 engaging the roller |5| of the spring contact |52, so as to momentarily close the circuit as the lever LS is shifted from any operated position to another position. For each lever there is a Small initiating relay |53, energized by a pick-up circuit, readily traced from B to N on the drawings, each time the lever is shifted to a different operating position. This lever relay |53 is stuck up through a circuit including its own front contact |54 and a limiting resistance |55 and the heel of its front contact |54 is connected by wires 245, 246 and |56 to a corresponding contact point |41 for the arm |43, this same limiting resistance |55 preferably being also included in the pick-up circuit of this relay, as shown. When any one of the several lever relays (such as |53) are energized to apply a battery having a terminal B through a front Contact, such as |63, to a bus line |60 leading to a starting relay X, the other terminal of which is connected by a wire |6| through the contacts |44|45 and the arm; |43 to the other side of the battery N, such starting relay X is picked up and is then stuck up through a stick circuit including the contact |83 and the stick Contact |12 of this relay X, readily traced. In other words, whenever any lever is shifted to a different position, the starting relay X is energizedv as soon as the shaft of a master selecto-r reaches its initial or zero position, if not already there, and if this relay X has once been picked up and stuck up it will remain up so long as one of the lever relays (|53) is up, even though contacts |44|43|45 are open. The purpose of this arrangement is more .conveniently explained hereinafter. A push button |62 is also provided whereby the dispatcher may himself pick up the relay X at the beginning of the next revolution of the master selector.

The location of trains is indicated by repeating at the central station or dispatchers olce the operation of selected track relays. If desired, each track relay on the whole stretch of trac-k may be repeated, and the presence of a train occupying each track section may be manitested in theldispatchers office by lighting a lamp at the place on the track diagramv corresponding to that particular track section. For the sake ofv simplicity, yI have shown provisions for indicating the presence of a train on a siding, on the main track opposite the siding, on the detector track circuit, and at any point in the stretch of single track betweensidings, the direction of the train as well as its presence being indicated in the last case. It is contemplated that a track diagram of the railroad under the operators jurisdiction will be displayed in a convenient place before him, and on this track diagram will have small lamps |54, |65, |65, |51, etc., as shown in Fig. 4A which whenlighted indicate that a train is` occupying a corresponding portion of the track. In the case of a stretch of single track between sidings, two lamps |68 and |69 are provided, with arrows or other designation, as shown in Fig. 4A to indicate'the direction of train movement, one lamp being automatically lighted, as hereinafter explained, when the train is traveling in the direction indicated by its arrow at any place along the stretch of single track. The lamps |64, |66 and |68 are controlled by small deadbeat polar relays |14, |16 and i1`8, respectively, these relays being connected to the 2nd, 4th, and 3rd contact points for the selector arm respectively. For reasons explained hereinafter, the lamp for the detector track circuit at least, and if desired all of theY lamps, has in series in its lighting circuit a slow-acting ashing relay FR, with a push button arranged to be held in its actuated position when once depressed but not attracted by the relay to such position.

Extending from'the tower along the track'are three wires, conveniently called the control wire CW, stepping wire PW, and the common wire CL. The control wire CW is connected to the contact ring |4| of the selector arm |49 in series with the upper winding of a diiferential bell-ringing relay BR, having a biased polarized armature |16 which closes the circuit to a single stroke bell, or other audible signal, when attracted in opposition to the bias of spring |1|. The stepping line PW is connected to the contact ringer |38 and also by wire |18 to the brush |33. The common line CL is connected in series with the other winding of the bell-ringing relay BR through wires 242 and 243 to the neutral point of the main battery |88 connected tothe lever contacts. The common line CL isi also connected, by wire (not, specifically shown) to the polar lamp relays |14, |16

and |18.

Referring now tc the selector at the sidings, the shaft |82, indicated diagrammatically by a dash line, is biased to turn in a clockwise direction by a suitable means.. As shown, the magnet |83 energized from a local battery is arranged. to attract an arm |84 against the opposition of the spring |85, breaking its own energizingv circuit at the contacts |86 in so doing. A pawl, |81, reciprccatedas the arm |84 is intermittently attracted and retracted by the magnet |83, drives a ratchet wheel |88 clockwise and -tensions the torsion spiral spring |39, said ratchet wheel |88 being held by a spring pressed pawl |86. The other end of the spring |89 drives a gear |9| meshing through the intervening pinion |92 with the pinion |93 on the shaft |82. It will be readily understood, without further explanation, that the magnet |83 automatically reciprocates the pawl |81 and turns the ratchet wheel |88 until the back pressure of the torsion spiral spring |89 balances or exceeds that of the tension spring |85, whereupon the pawl arm lfails to complete its stroke, leaving the magnet |83 de-energized. Other means, such as a small motor and friction clutch, or clock winding mechanism of the usual construction, may of course be used. for giving the desired bias for turning to the-shaft |82.

Fixed to the shaft is an escapernent wheel |95 cooperating with a movable pallet |96 pivoted at |91, and biased in one direction by a spring |98 and at times attracted. in the other direction by a stepping magnetV |99. As the stepping magnet is alternately energized and de-energized, the pallet |96 is reciprocated, and the escapement wheel |95 allows the shaft |82 to turn step by step positively from one position to another.

Also fixed to the shaft is an arm 208 cooperating with a spring contact finger 26| in the initial or zero position to move that contact finger 20| from engagement with one xed contact 282, and hold it in engagement with another fixed contact 283. Another spring finger 294 is arranged to be moved out of Contact with its stationary contact 265 when the arm has made one step beyond its initial position. Spaced around the shaft, with the same spacing as the make and break points on a master selector and also the contact points for the arms of said master selector, are a plurality of contact points and spring ngers, these fingers and Contact points, together with their connections, corresponding with those for the selector arm |49, have also been designated lst, i

2nd, 3rd, 4th, etc. In the particular arrangement shown in the rst position 1st of each selector, a circuit connection is made at the master selector in the dispatchers oice from the lever LS. On the selector for the siding end corresponding to the lever LS, the first contact point hasa spring ngerA 1st, normally engaging the fixed' Contact 296 and also connected to one terminal of the relay SW corresponding to said lever SL, the other terminal of said relay being connected to the common line CL. The relay SW whenever energized, is stuck up through a local battery 298 and neutral and polar contacts 289 and 2 t!) in series with the spring nger lst and its stationary contact 296. As shown, the way station selector in Fig, 4B, which is assumed to correspond with the particular end of the miniature sidingy shown in Fig. 4A, has its second contact point 2nd connected to the contact n'ger of the, detector track relay of section d; and similarly the second contact point also marked 2nd of the selector arm |48 is connected to the polar light relay |14 controlling the light |64 corresponding to that detector track circuit. In a similar way, the corresponding control of contact points on the master selector are connected to corresponding control points on thevarious selectors through the system. While the master selector has a complete equipment of contact l points around the shaft, each selector will have only the necessary contact points for the control of the relays Z and SW at that point, and for the indications of train location to be reported at the vicinity of that point. l In the same way as the second contact 2nd of the Wayside selector is connected through contact to the negative N or positive B of a suitable battery having its neutral point connected to the common wire CL, the third contact 2O 3rd is connected to N when the contact 2|3 of home relay 2H is up and is connected to B when the Contact 2|4 of the detector track relay of section d is up and the contact 2|5 of relay 2S and contact 2|3 of relay 2H are down. This circuit arrangement as more clearly explained hereinafter applies positive potential to the third contact point 3rd when there is a west bound train in the stretch of single track O and applies negative potential thereto when there is no train in this section or there is an east bound train therein.

As a result of this energization of the third contact peint the lamp |68 at the dispatchers office is lighted only when there is a west bound train in the single track stretch O.

Operation of selecting system The operation of the selecting system is more conveniently described by starting with the master selector in the station DO in its initial or zero degree position, and assuming that all of the station selectors are at that time in the same positions. While the shaft |39 of the master selector is continuously rotating, the shafts |82 of the outlying station selectors are normally at rest,

assuming that the system is not at that time being used for the transmission of either control or train location indications. Passing for the present eX- planation of the reasons why the way station selectors are thus normally at rest, when the master selector reaches its zero degree position, as shown, the brush |33 rides on insulation |35 and disconnects the battery 229 from the stepping line PW. The cam |36 forces over the nger |38 and connects the stepping line PW to the contact finger 22| of the local starting relay X. Assuming that no lever has just been operated, the relay X is de-energized and its nger is in the lower position as shown, energizing the stepping wire PW with current of negative polarity which passes over wire 222 through contacts |39-|38, wire PW, contacts 20 |-203, wires 223 and 224 through the polar starting relay SR to the common line. This impulse moves the armature of this polar relay SR to the left hand position as shown.

Although the neutral contact 228 of this slow acting polar starting relay SR is picked up for a time, the stepping magnet |99 is nevertheless disconnected from the stepping line PW, each of its three multiple circuits being broken. The

starting relay SR is made suiciently slow acting that it will not respond to the short stepping impulses, that is, so that it cannot pick up its neutral contact 228 in response to a stepping impulse and will pick up only While the contacts |38-|39 are closed. One of the three multiple circuits for the stepping magnet |99 may be traced, from the stepping lines PW to the finger 20|, through contact 282 (now open because selector is in its initial position) and wires 226 and 221 to magnet |99 and to common line CL. Another circuit is from contacts 24H-293 along wire 223 through neutral contact 228 and wire 229 to the polar armature 239 in the left hand position, wire 23| through front contact 232 of initiating relay IR and wires 233, 234 and 221 to the stepping magnet. A similar circuit is through the polar armature 230 in the right hand position through the wires 235, 234 and 221 to the stepping magnet |99. All of these circuits being open under the conditions assumed, the stepping magnet |99 is not energized, and the shaft |82 and the arm 290 remain stationary. As the master wheel advances from the zero position shown, the cam |36 releases the roller |31 which opens contacts |38-|39 and the stepping wire PW is de-energized long enough for the relays SR to drop. Then, the brushes |32|33 intermittently connect the battery to the stepping wire, but since the stepping Wire PW is not connected to the stepping magnet |99, the wayside selectors will remain at rest.

Transmitting a control code.--Assume now that one of the levers, as LS is operated. This operation of a lever LS, from any position to another, momentarily closes the contacts |52 and energizes the relay |53, which is then stuck up through its stick contact |54 in series with the limiting resistance |55. With this lever relay |53 up, the relay X is picked up and stuck up by completion of its energizing circuit at the beginning of the next revolution of the master selector, namely when contacts |44|45 are bridged by arm |43. Also, when the master selector approaches its initial or zero degree position, the brush |33 rides on the insulation |35, cle-energizing the stepping wire PW and the stepping magnets |99 of any selectors then in operation, producing the nal movement of the selectors in operation to the initial or zero position, in which the arm 209 engages the spring nger 29| and shifts it to the position shown. When the arm |43 which remains in motion engages the contacts |44 and |45 the starting relay X is energized, one of the levers having been operated, which relay X then remains stuck up through the stick circuit |63, |69, X and |12. The cam |36` then shifts the spring nger |38 to its circuit closing position; and the relay X being energized the stepping wire PW is energized with an impulse of opposite polarity to normal, conveniently called positive. This impulse energizes the polar relays SR of all of the wayside selectors, in each case shifting the armature of the polar relay to the right dotted position, whereupon current flows from the stepping Wire PW through contacts 29|-293, wire 223, neutral contact 228, wire 229, polar armature 230 to the'rght, Wires 235, 234 and 221 through the stepping magnet |99 to the common line CL and back to the tower battery 229, thereby operating the escapement and advancing the shaft |82 a half step. The spring linger 29| is now released and engages the contact 202, connecting the stepping magnet of the selector directly across the stepping wire and the common line. This explanation applies to all of the wayside selectors because a positive impulse over the stepping wire PW starts all of the selectors, which selectors if once started establish the stepping circuit as just explained. Then when the master selector advances, the cam releases the spring contact arm master selector, so that when the arm |40 of the A master selector is inthe position corresponding tothe lever just operated vassumed to be rst position marked lst, corresponding to the lever LS, the arm 200 of one of the selectors is in the same corresponding position engaging a spring finger 1st and establishing at that particular selector a partial circuit from the control wire CW to the common line CL through the particular relay SW or Z, in this case SW, which corresponds to the lever in question. Thus when the selector arm |40 of the master controller is in its rst position, the arm 200 of the selector shown is in position rto engage the finger 1st, thereby completing the circuit from the main tower battery |80, from the positive or negative terminandopendingupon the position of the lever LS itself, through the lever LS, wire 231, through selector arm |4, contact ring |4|, wire 238, upper winding of thediierential bell relay BR, control wire CW, contact ring 239, selector arm 200 of the selector of the siding corresponding to the lever LS, spring linger lst, wire 240, relay SW, and wire 24| to common line CL thence along wire 242 to the Alower winding of the differential bell relay BR and wire 243 to the neutral or middle terminal of the main battery |80. The relay SWisthus energized, either positively or negatively depending on the direction in which the lever LS was moved; and as the arm of the way station selector advances, in synchronism with the master selector, the springlnger Y1st is released and closes a stick circuit for the relay SW, readily traced on the drawings, and which'has heretoforeV been spe` cically traced. While the master selector is in this position corresponding to the lever LS operated, the arm |43 engages the contact |41 and establishes a circuit for shunting out and deenergizing the lever relay |53 starting at the positive side B ofthe battery, through the limiting resistance |55, front contacts |54 of the lever relay |53, wires 245, 246 and |56, contact point |41, arm |43, contact ring |46, wire 241, through front contact 248 of relay X to the negative N oi the battery. The shunting circuit just traced shunts the current, which flowed through the relay |53 and resistance |55 in series, away from the winding of this relay |53, thus causing deenergization thereof. With the relay |53 assuming its'de-energized condition the relay X is deenergized thus opening its stick contact |12 and the shunting contact 248. With the stick contact |12 once open the relay X will not again assume its energized vcondition until the rst return of the master selector to its starting position after alever relay, such as |53, has been energized. Obviously, the lever relay |53 could be de-energized by opening a stick circuit, as well as by shunting its win-ding, but this modified construction is :for convenience omitted from the drawings. De-energization of the relay X, by dropping of its contact 22|, causes a negative starting impulse to be transmitted at the beginning of the next revolution of the master se` lector, which negative .impulse will only start those way'station selectors fror'ri which an indication is to be transmitted-to the dispatchers ofce.

` When the mastersele'ctor, and also each of the way station selectors, again reaches its initial or' zero position, the arms 200 of each of the station selectors shift the spring contact disconnecting the stepping magnet |99 from the steppingv Wire PW andA connecting it to the pola-r starting relay SR. When the cam |`36` shifts the contact lnger |38, av starting impulseof a normal or negative polarity is transmittertbecause the relay X is die-energized, assuming that no other' lever hasbeen operated in the meantime.4 This starting impulse of normal negative polarityop-I crates the Apolar armature of the polar relay SR' tothe left as shown, so that when the short stepping impulses are 'applied to the stepping wire PW, the stepping magnets |99 of the various' selectors are not energized. Thus, each selector' remains at rest in the initial or zero position..

The levers may be operated at any time simultaneously, or in rapid sequence, or n any order withoutY interfering with the operation of the system. Each time the lever is operated, all of the selectors are started when the master selector reaches its zero position. If another lever is moved immediately after the' first, `the lever relay corresponding to that lever will be energized during the same revolution of the master controllen, if the contact arm has not passed by the position corresponding to that second lever by the time it is Vshifteclr If the contact arm has passed by the selecting position corresponding to the seco-nd lever pulled, then the lever relay for that lever is not shunted out because the relay X is still Vdown and the shunting circuit is open at contact 248, this relay X however picks up at the beginning of the next revolution of `the master selector, whereupon the selectors at the way station complete a second revolution, during which revolution the lever relay is shunted out and caused to drop; and the same operation is repeated until all of the levers operated have had a chance to energize their corresponding relay, after which the `relay X is de-energized and the selectors at vthe way stations-automatically stop and remain at rest until again started by operation Vof a lever, or by the operation of a track relay,

as about to be described.

In the case of control impulses for energizing the relays Z orr SW, current is supplied from the main battery in the tower, and the same current traverses the upper and lower windings of the bell relays BR. The windings of this relay BR are so Wound and connected that the flow of this control current, of either polarity, out the control wire CW and back through the common line CL, 242, 243, produces opposing fluxes and consequently these fluxes do not actuate the biased polar armature. Consequently, the bell is not sounded when control impulses are transmitted., This bell BL on the other hand is sounded in response to operation of the relay BR. when an indication impulse is received from a way station selector because this current impulse does not pass through wires 242-243 including the lower winding oi this relay BR, thus leaving only one of these uxes elfective.

y Transmitting a train indication coda-Referring now to the operation of transmitting indicationsin response to the operation of track relays, thesystern is so arranged that the selector at the particular place Where a track relay operates is automatically started in synchronism with the masterselector, makes one revolution, and then automatically stops. By providing enough contacts on the selectors, as many track circuits may be repeated as desired. As shown, provision is made for indicating at the central station on the miniature track layout the energized or de-ener-A gized condition of the track relay for the detector track section d, which indicates the arrival and departure of trains at the east end of the siding SD and shows when trains have cleared the fouling points. It is also considered desirable to repeat in the tower the condition of the track relays for the track sections of the siding as indicated by the indicating light |66, and of the main track opposite the siding as shown by light |65. Since there is preferably a selector for each end of the siding, in order to economize in wire, the selector at one end of the siding takes care of the track circuit of the siding, as shown, and the selector for the otherend of the siding takes care of the track circuit for the main track opposite the siding, as Well as for the detector track circuit at that end. These indications tell the operator what sidings are occupied and keep him informed of trains waiting to make meets. vIn order that the operator may be kept fully advised or" the location of all trains, two indicating lamps |68 and |69 with arrows or the like signifying direction, are providedfor each stretch of single track between sidings, and these lights |68 and |69 are lighted whenever a train occupies any portion of this single track stretch according to the direction of movement of that train. This is accomplished by taking advantage of a feature of the A. P. B. system which causes de-energization of the line relay 2H with a westbound train in any portion ofthe single track (see Fig. l) and the line relay 5H for eastbound trains. The line relay 2H is also de-energized while an eastbound train is between the signals 2 and 4; but the relay 2S, controlled in the same way as the relay 4S, and located at the signal 2, will be energized by such an eastbound train, andwill be maintained energized until this train has passed the signal 4. In other words, a Westbound train in the stretch of single track between the sidings SD and SD1 (see Fig. 1) will de-energize the line relay 2H, and at that time the stick relay 2Swill also be de-energized; Whereas an eastbound train will energize the stick relay 2S during the time that the line relay 2H is de-energized. A circuit including the back contacts 2|3 and.2|5 of the relay 2I-I and 2S, respectively, will be closed therefore only if a westbound train is at some point in the stretch of single track. This circuit also preferably includes the front contact of the track relay for the detector track section d, as shown in Fig. 4B to assure that the indicating circuit in question will not be momentarily established by an eastbound train because of dropping of the line relay 2H before picking up of the stick relay 2S.

Assuming a way station selector at rest as shown in Fig. 4B (no control impulses being transmitted), when the detector track relay of section' d for instance drops, the make-beforebreak contacts 25E) momentarily close an energizing circuit from B, through contact 250, Wires 25|, 252 and 253, relay IR to N, for a quick-acting initiating stick relay IR, which is stuck up through the contacts 204--205 of the selector. When the master selector neXt comes to its initial or zero position, and a long starting impulse either positive or negative is transmitted, the neutral contact of relay SR is picked up. yIf the starting impulse is a negative one and the starting polar relay is energized to the left and with the relay IR energized establishes a circuit heretofore traced to the stepping magnet, permitting that selector to operate. If the starting impulse is a positive one the way station selector will start in synchronism for reasons already described under transmitting a control code. As the arm of that selector moves, it breaks the stick circuit for the relay IR, so that the selector makes only one revolution and stops. The detector track relay of section d being de-energized,

one of the contact points, shown in this case as the second point 2nd, is connected tothe positive terminal B ofthe battery, the middle terminal of which leads to the common line CL thereby energizing the polar light relay |14 with opposite, that is positive, polarity, which reverses the light relay |14 and closes a circuit through the lamp |64 in series with the flashing relay FR. The flashing relay FR intermittently opens and closes the circuit through the lamp |64, thereby ashing the lamp. This circuit may be traced as followsz-B, contact 251 to the right, wire 258, lamp |64, wire 259, winding of FR, wire 260, contact 256 down, wire 26|, to the negative terminal N. When the operator pushes down the switch 255, the ashing relay contacts 255 and 256 are stuck closed and the light |64 is steady, said switches 255 and 256 being held in their attracted position magnetically. This flashing relay FR is so constructed that its magnetism due to its normal current is suiflcient to attract armature 256 but not armature 255, but is of sufficient magnitude to hold the armature 255 attracted if once closed. The impulse transmitted over the control wire through the lamp relay |14 passes only through the upper winding of the bell relay BR, and not also through the lower Winding as is the case when a control code is transmitted, and consequently operates its armature. The armature of the bell relay BR is preferably made polarized, in order that the bell BL may ring when the track relays drop, sending a negative impulse, and not when track relays pick up and send a positive impulse. This feature is provided in contemplation that the operator wishes to be promptly informed of the entrance of a train into a particular portion of track, but is not interested in the picking up of track relays by trains, except as may be readily determined by inspection of the diagram.

The iiashing relay arrangement is. provided in order to enable the operator to readily determine, upon sounding of the bell BL, which light has just been lighted. It will be evident that, with several trains on the railroad, there will be many lights displayed on the track diagram at the same time; and it would be diicult for the operator to determine what light has just responded to a train movement. With the ashing light, however, the operator can instantly pick out the particular track location where a train has just entered, and having noted this condition, may stop the flashing light and make ready for the next indication by pushing in the switch 255. Although only one flashing relay FR has been shown, there is preferably provided one for each indicating lamp for the detector track circuits.

When the detector track relay of section d picks up, its make-before-break contact 250 momentarily energizes the initiating stick relay IR, the selector is started, and the indicating impulse of the other or negative polarity is transmitted, reversing the armature of the lamp relay |14 and vextinguishing'the lampi land releasing the switch 255 of the corresponding ilashing. relay FR.

The `sameiexplanation applies to the droppingand picking Aup of the track relay of section c for the siding. Whenever the line relay 2H is energized or de-energized, the selector is started in response to momentary closure of contact 264; and if when this relay is de-energized the I-stick relay 2S has its back -contactclosed, thenan impulse of the positive indicating polarity yis transmitted to the corresponding lamp vrelay |18, lighting the lamp |88 having the arrow signifying westbound traino in the stretch of single track in question. With respect to the side track of the passing siding, the make-before-'break contacts 263 serves a purpose similar to that of contact 250, and the contact 265 vapplies B or N to the fourth contact-the same as contact ||l| applies energy to the second contact point.

This selector system described vprovides distinctlcircuitsat dilerent times between the central station and the way stations, and these circuits may be advantageously utilized to transmit a plurality of controls or indications. The relays, as SW and Z -to rb e controlled are made quick-acting, as are like-wise the lamp relays, so that the selector arms do not have to remain in their diierent contacting positions so longas to unduly lengthen the time of` one revolution or cycle. If desired, two quick-acting polar relays, leading to separate contact points, may be emplo-yed instead of the neutral polar relays SW and Z, the spring arms controlling the stick circuits likewise being omitted. It is ofV course understood that the same or even a greater number of rcontrols may be given' by two two-position polar relays as by one three-position polar neutral relay. The number of contacting positions of the selector'arm required to give the desired number of controls and indications for alength of railroad that an operato-r lcan conveniently handle, together with a speed of rotation of the .master selector shaft possible with ordinarily quick-operating relays, enables a change-in control or indicating to become effective so quickly that the maximum delay is something less than three or four seconds, and this is quick enough for this type of work. If more indicating points are desired, an additional selector arm may vbe carried on the master selector shaft and an additional control wire employed with the same type of way station selector.

Reviewing briefly the selector system of which one embodiment has been illustrated in Figs.

4A and 4B, this. system is based on the underlying principle of transmitting distinctive codes whereineach` code constitutes a single electric impulse of which the distinctiveness depends von 60 the` time that this electric impulse is transmitted in a cycle of operation of the synchronous selector system. Since each code is characterized by a single impulse having a definite relation in time to the last initiation of a revolution of the v master and way-station selectors Vit is readily appreciated that a large number of these selective codes or impulses may be transmitted substantially simultaneously, that is, may all be transmitted during a single revolution -ofv the various selectors, of Lwhich the time of one revolution may be, say, from one to ve seconds. Y As heretofore pointed out, the master selector located in the tower DO is constantly operating and its Contact arms |40 and |43 are continuously operated :at a xed speed, Whereasall of .the waystationv selectors are normally at rest. It readily appears :that if an indication is to be transmitted from a vway station .selector to the dispatchers ofce, .for instance, to indicate the arrival of a train,'itlis1 only necessary' for that particular way station. selector to operate. On the other hand, iffit fisdesir'ed to pick up a control relay at one of theway stations it is necessary that all of the way-station selectors be in operation in order that ythe distinctive code may have an opportunity to reach-the particular way station selector and relay whichA itis tol-control in response to the 'operation of Va lever in the dispatchers ofce; By reason of the fact that all of the Way Vstation .selectors must operate when a control slow acting polar relay SR, and thev other distinctive .starting impulseconsists in the transmission ofapositive impulse over the stepping Wire :PW lof suflicientduration to pick up this same startingrelay SR toits right hand position.

Normally, that is when no code impulses are to be transmitted, each revolution of the master selector :during the transmission of its stepping impulses first transmits a negative starting impulse Awhich holds the polarcontact. 23e of the slow acting polar relay SR vtothe left and picks i up the neutral contact 2280i thisrelay and again drops this Vneutral contact. Thislnegative starting impulse mayibe considered'to be a synchronizing.impulse because it is transmitted at each revolution -of Athe master selector so that when f" a train `indication is to be transmitted from a way station selector this way station selector may start inresponse to energization of the initiating relay IR. but -may start in synchronism in responseto ythe lifting of the neutral contact 228 `v of the starting relay SR. The net result is that if the initiating relayfIR is picked up and stuck up, as for .instancexinxresponse;to dropping of the detectorftrack relay of section d, the way station selectorassociated therewith is started upon'the transmission of the rst negative starting impulse thereafter, and this way station selector is again stopped the rst time it reaches its zero degree position after the stick circuit for initiating vrelay IR. is broken. On the other hand, s.

when a control code is totbe transmitted from the dispatchers office `DO sto a Vparticular control relay located at a wayside station the picking up of the `.relay ,X in response to the operation of the lever "at the dispatchers office will cause a positive starting impulse ofsuiicient duration to pick up `the neutral armature 228 of the relay SR at each of the various way station selectors to ,be transmitted so that all of the way station selectors ,are started vin synchronism with the master vselector and will continue in operation forat least onerevolution. l

Bearing in rmind this broad underlying principle of transmitting starting impulses of two distinct kinds, oneof which is'A primarily used for conditioning apparatus at all of the way stationselectors so that any one particular selector may be `initiated because an indication is to be transmitted from thatY selector to the dispatch- .ers olicaeand .,lwill. operate throughfat leastv one aso revolution, and the other distinctive starting impulse of which is used for starting all of the selectors when a control impulse is to be transmitted from the dispatchers office, it readily appears that many different types of apparatus might be used to carry out this theory of operation wherein only a master selector is continually operated and the way station selectors are only in operation when necessary to transmit l0 or receive a distinctive code. For instance, in-

stead of operating all of the various way station selectors in response to stepping impulses transmitted from a way station selector each of these various way station selectors might be operated 15 solely by local power and local constant speed mechanism, such as a motor driving a normally locked shaft through a slip friction clutch which shaft is released by a starting impulse, suitable Clockwork mechanism, or the like, so long as the selector operating mechanism functions properly to keep its rotating contact arm in synchronism with the master selector arm after having started in response to a. starting impulse transmitted by such master selector. The local starting relay X located in the dispatchers office is primarily provided to insure that all of the way-station selectors operate through at least one revolution after each change in lever positions of the equipment. Attention is particularly directed to the fact that the relay X is not picked up until the way station selector arrn |43 has reached its Zero degree or starting position in which it bridges the contacts Idd-|55; and that the relay X will kremain energized through its stick circuit including the stick contact '|12 until all of the lever relays, such as relay |53, have again assumed their de-energized condition. From this it'readily appears that should the arm |43 have passed a 40 particular Contact, the lever of which is operated immediately after this rotating arm |43 has passed such Contact, the lever relay for that contact, such as |53, Will remain stuck up even though all of the Way station selectors have 45 operated during the preceding revolution of the master selector, that is they will be operated through a second revolution, so that the code transmitted from such lever may reach the proper way station selector and control relay. During this second revolution the wiping of the contact arm |43 over this'contact, such as |41, shunts the winding of this lever relay and causes it to assume its de-energized position. In connection with this subject of starting and stopping the various way station selectors, it is desired to point out that the relation between the spacing of the various contacts in the circumference about the selector shafts |30 and |82, the time required for picking up and dropping of the various relays, the inductance and capacity of the various circuits, battery voltage, and the like, will be so chosen that the various Way station selectors will always start in synchronism with the masterv selector, will remain in synchronism during the revolution or revolutions through which they are to operate, and will be brought to stop when they again reach their zero degree position. In this conection it should be noted that if a lever is operated in coincidence with the transmission of a Starting impulse the relay X will not pick up until the master selector has completed that revolution, in which event the control code will not bertransmitted until during the following revolution of the. master 7.5 selector'. In other words kthe relay cannot pick up during the time contacts |38l-39 are closed and further it cannot drop While these contacts are closed, and therefore it is not possible for the relay X to change either a positive or a negative starting impulse into two short impulses one of which is positive and the other of. which is negative.

Referring now to the Way station selectors, of which only one has been illustrated in Fig. 4B, it is desired to point out that the control relay SR is sufficiently slow acting so that it will not pick up during the transmission of one or a series of stepping impulses, but will pick up its neutral transmission of either a positive starting impulse or a negative starting impulse. Further, since the initiating relay IR if in its energized condition through its front contact 232 may start the associated way station selector and since this initiating relay IR will have its stick .circuit broken at the zero position and before the shaft reaches the position marked lst, it appears that the way station selector will operate through at least one complete revolution after each track relay change, and will therefore assure transmission of an indicating code from such way station selector to the master selector.

contact 228V upon the Automatic recorder In order for the operator to handle the traflic expeditiously, it is necessary for him to have complete information of the location of each train. The existing location of trains on the railroads is very clearly exhibited to the operator by the lighted lamps on the track diagram, as already described. These lighted lamps do not, however, tell what particular train is at that point on the track, nor do these lamps show how long the train has been at that place, nor the direction it is headed, With the exception of the direction lamps for the single track portions.

While the position of the levers LS and LZ show what are the existing positions of the switches and directions of traffic, and the lights on the track diagram indicate the location of trains, the operator frequently has occasion to make various notations of train movement forecasts, train delays, time allotted tol work trains, and the like. It is also necessary to have a complete record of train performance. Although the operator may keep a regular train sheet, making such notations thereon as he Wishes, and operate the the system with a high degree of eiiciency, it is proposed to make an automatic record of train operation on the graphic chart from and in such a way that the operator can use this record for convenient reference, and make his notes on the same chart.

Fig. 5 shows a track diagram with the levers LS andLZ--LZ2 conveniently disposed with relation to this. diagram. Below this track diagram and lever board, which is preferably disposed vertically or on an inclined panel, and on the table in front of the operator, is a miniature track diagram (see Fig. 6 of the drawings). This still smaller miniature track diagram is disposed directly above an opening exposing a recorder sheet 21u ruled horizontally to indicate increments of time, and vertically to indicate track locations. Thisrecorder sheet is fed from a drag roller 21| over a hat surface 280 affording a backing to the sheet so that it may be marked upon; and is wound up on a roller 212, moved continuously gradually or step by step by suitable clockwork mechanism v213, this driving roller preferably having teeth (not shown) engaging holes in the edge of the paper 210. While any suitable marking means, operated from the lamp relays |14, |16 and |18 may be employed, it is preferred to make marks on chemically prepared paper by the direct flow of electric current. As shown, in multiple with each lamp such as |69, for instance, are a pair of contact points 215, preferably imbedded in a. bar 216 of insulating material to afford a smooth marking contact surface for Vthe paper, which contacts 215 bear on the underside of the paper and allow current to flow through the paper between these points when and so long as the corresponding lamp relay is energized with one polarity of current. Any suitable chemically prepared paper may be employed to produce a colored mark, due to the electrolytic action, or the like, by the flow of current. For example, the paper may be moistened by a wick or pad 211 bearing on its underside, this wick containing a mixture of starch paste and solution of potassium iodide which mixture is contained in the tank 218, the moistened paper in turn being dried by ironing, as by an electrically heated bar 219; or, if desired, the paper may be impregnated with the desired chemicals and the wick 211 be used for moistening purposes only for reducing the resistance to electric current flow. Obviously, the current may be caused to flow between the contacts bearing on opposite sides of the paper, or electrically operated pencils or pens may be employed, or various other expedients employed in the art of recording may be employed.

So long as a train occupies the portion of track controlling one of the lamp relays, a mark is made on the chart along the vertical line corresponding to that place on the railroad. The ends of this mark show the time when the train entered and left the track section. These marks when manually connected up by sloped lines provide a step-like time distance curve for each train', as indicated on the chart in Fig. 6; and it will be evident that by reference to this chart, the operator can conveniently ascertain the number of the train then occupying a given track section. For example, if the lamp for the siding SD is lighted, and the operator wishes to know which train this is, reference to the chart shows the number of this train and also how long that train has been on the siding. The operator can also make such notations or marks on the chart as necessary to record forecasts of meets, train delays, and the like, so that when it is time to manipulate the levers, in view of a certain train having reported in, he can determine from these notes what he had planned to do.

As an example of how the recorder makes a record, lines have been shown on the chart 210 indicating that an east bound train #80 met a west bound train #90 at the passing siding SD,

the train numbers in practice of course being entered upon the chart by the dispatcher from his knowledge through other channels. It Iis noted that at 12 oclock east bound train #80 entered the fouling section a at the west end of siding SD and train #90 occupied the single track stretch O, moving Westward. At 12:02 train #90 entered the detector track section d, entered the siding c at 12:03, cleared the single track section O at 12:03, cleared the fouling section d at 12:05, and occupied the siding until 12:19. Also, train #80 entered the main track b at 12:06, cleared the fouling section a at 12:07, entered the fouling section d at 12:10, cleared the main track b at 12:11, entered the single track section O at 12: 13, left the section d at 12:14, left One marked advantage of making an automatic record inthis way isthat it leaves the operator free to devote his attention to handling the levers and planning train movements. His attention is not distracted at diflicult times by the necessity of recording the time of arrival or departure of some train. Another very important feature of this method of making a record, is that it is easily read and is more reliable than a hand made l record, because it is not subject to false and mistaken entries as is the case with handmadev records.

Since the recorder shown accurately records the entrance and departure of the front and rear end, respectively, of trains moving into and out of successive track sections, this recorder also` records the speed of the train providing its length is known, as is usually the case in railroading. For instance, the overlap as to time during which a train occupies two successive track sections in-l dicates that during this time the train occupied! both of these sections, and therefore if its length and time of transfer from one section to the next is known .its speed is readily calculated. In the same'way, if the length of certain track sections is known, as will be the case in practice, it is a very simple prob-lem to determine the speed of a train regardless of its length by the record available; and after its speed is known it is an easy matter to determine its length for reasons already given.

The particular embodiments of the invention shown and described are merely illustrative; and various additions, adaptations, and modifications may be made in the particular construction and arrangement of parts and circuits shown and described to meet the exigencies of a particular installation without departing from the invention.

What I claim isz- 1. In an animated train diagram, the combination with a plurality of indicating lamps for in-i.`

dicating train movements, a circuit for each lamp including a source of current, the winding of an electro-responsive device and a back contact of this same device; whereby said lamp is intermittently energized when said circuit is closed; and

manually operable means for each lamp which if operated allows such lamp to be lighted continuously so long as its circuit is otherwise complete.

2. In an animated train diagram, the 'combination with a plurality of indicating lamps for indicating train movements; a circuit for each lamp including a source of current, the winding and a back contact of an electro-responsive device; wherebyv said lamp is intermittently energized when said circuit is closed; and manually operable means for each lamp which if operated allo-ws such lamp to be lighted continuously so long as its circuit is otherwise complete, and which means vis restored to its normal condition when the energizing circuit for such lamp is broken.

3. In a system for transmitting a plurality of distinctive indications over the same line circuit wires, the combination witha master circuit selector and a plurality of Way station circuit selectors, means governed by said master selector for transmitting a starting impulse for starting a way station selector only if vsuch way station selector has` been conditioned for starting, and means for conditioning for starting a way station 

